Searching for supermassive charged gravitinos in underground experiments

We examine possible experimental signatures that may be exploited to search for stable supermassive particles with electric charges of 𝒪(1) in future underground experiments, and the upcoming JUNO experiment in particular. The telltale signal providing a unique signature of such particles, would be a correlated sequence of three or more nuclear recoils along a straight line, corresponding to the motion of a non-relativistic ( β≲ 10^-2 ) particle that could enter the detector from any direction. We provide some preliminary estimates for the expected event rates.